Conventional (“wireline”) telephone systems require a physical connection (a “landline”) to be established between the telephone unit and the local telephone company central office. These systems are particularly expensive in rural areas where costly transmission lines must be constructed. Wireline telephones include those that are connected by copper wire, fibre optics, and cable and are not limited to simply metallic connections.
Since conventional wireline telephone systems are fixed in place, those who require the use of a mobile telephone often must incur additional expense by subscribing to a cellular telephone service and by purchasing new telephone equipment to connect to a wireless telephone network, such as a cellular telephone network. In addition to the increased cost, users often require two telephone numbers, one for each of the wireline telephone service and the wireless telephone service. This requirement for multiple numbers can be inconvenient.
Another type of telephone system is comprised of a conventional telephone design internally configured to access a wireless telephone network. A Qualcomm™ QCT-1200 is an example of such a product. While this system avoids the need for costly transmission wires, its limited features make it truly beneficial only in applications where landlines do not exist. At least one Qualcomm telephone model permits the addition of a wireline telephone extension to the wireless unit.
Similarly, Canadian patent no. 1250380 issued Feb. 21, 1989 to West and Shafer and U.S. Pat. No. 4,658,096 (issued Apr. 14, 1987 to West and Shafer), U.S. Pat. No. 4,737,975 (issued Apr. 12, 1988 to Shafer), U.S. Pat. No. 4,775,997 (issued Oct. 4, 1988 to West and Shafer), U.S. Pat. No. 4,922,517 (issued May 1, 1990 to West and Shafer) and U.S. Pat. No. 5,117,450 (issued May 26, 1992 to Joglekar and Aseltine) also disclose an interface that permits an existing conventional wireline telephone to access a wireless telephone network. The interface simulates the conventional wireline telephone environment for users that are not comfortable with wireless telephone functionality. Features such as a dial tone generator and simulated ring tones achieve this end. However, this system also suffers from the limitation that it is not portable and therefore can not take advantage of the mobility that a wireless telephone network affords.
To achieve portability, U.S. Pat. No. 4,718,080 (issued Jan. 5, 1988 to Serrano and Holman) discloses a telephone interface system that may be installed in an automobile or other vehicle permitting a wireline telephone unit to interface with a wireless telephone network.
Alternative systems and methods for interfacing between wireline and wireless telephones are desirable.